Solution: Use the segmentation method:

Original formula =6.5x 1.8.

=6.5x2x0.9

= 13x0.9

= 1 1.7。

Related information:

Simple calculation is a special kind of calculation, which makes use of the algorithm and the basic properties of numbers, thus making the calculation simple and making it easy to calculate numbers from very complicated formulas.

Simple calculation by law;

1, Multiplicative Distribution Law:

The most commonly used method in simple calculation is multiplication and distribution law. Multiplication and division means ax(b+c)=axb+axc, where A, B and C are arbitrary real numbers. On the contrary, axb+axc=ax(b+c) is called the inverse application of multiplication and division (also called finding common divisor), especially when A and B are complementary to each other, this method is more useful. Sometimes the law of additive combination is used, for example, a+b+c, and B and C are complementary, so that B and C can be combined and multiplied by A. If+in the above formula is replaced by X, it can also be simply calculated by the multiplicative associative law.

2, the law of multiplication and association:

The multiplicative associative law is also a simple method, which is expressed by letters as (a×b)×c=a×(b×c). Its definition (method) is: multiply three numbers, first by the first two numbers, then by the third number; Or multiply the last two numbers first, and then multiply the first number, and the product remains the same. The order of multiplication operations can be changed, and the application of multiplicative associative law in daily life is not extensive, and it mainly plays a simple role in some complicated operations.

3. Multiplicative commutative law;

Multiplicative commutative law is used to exchange the positions of various numbers: a× b = b× a.

4. additive commutative law;

Additive commutative law is used to exchange various numbers: a+b = b+a.

5, additive associative law:

(a+b)+c=a+(b+c).